自然循环蒸汽发生器倒U型管内倒流特性的无量纲分析

针对自然循环工况下，蒸汽发生器部分倒U型管内存在倒流现象，利用无量纲分析方法建立管内流体控制方程，提出了阻力数和传热数等无量纲准则，并对蒸汽发生器倒U型管倒流的影响因素进行分析。结果表明，阻力数对倒流发生的无量纲进出口压降和流速有较大的影响；传热数对倒流发生的无量纲进出口压降有较大的影响，而对流速影响较小。

Dimensionless Analysis of Reverse Flow in Inverted U-Tubes of Steam Generator Under Natural Circulation

For natural circulation, it is shown that reverse flow occurs in the inverted U-tubes of the steam generator (SG). The dimensionless analysis was used to deduce the expression of the flow equation, and the factors affecting reverse flow characteristics were also studied, which were the Π_f and Π_h. The results show that, the non-dimensional Δp of extreme point is effected by Π_h and Π_f, but the non-dimensional velocity is effected byΠ_f.